In the past, Micro-Electro-Mechanical System (MEMS) gyroscopes (gyro) have been widely available in the industry, but with their unavoidable drift, often provide insufficient performance for use for head tracking systems, unless some calibrating or corrective augmentation of the MEMS is employed.
Head tracking has been known to be used for gyroscopic or inertial measurement augmentation. Such augmentation has been done with optical, ultrasonic, and magnetic techniques, each with various deficiencies.
One common deficiency is that they often are limited to use in controlled environments, such as an aircraft cockpit. When an open and/or uncontrolled environment exists, such as with a person walking outdoors, the necessary hardware to perform precise head tracking is often expensive, heavy and power hungry. With these deficiencies, prior art head tracking systems may have been believed to be unsuitable for augmentation of inertial measurement units for many head tracking systems.
The present invention overcomes one or more of these problems.